Strength - Affects your melee attack power, knockdown power, and attack speed of heavy weapons. This is an important statistic for fighters.
Agility - Affects attack speed and evasion rate. Scout benefit from high Quickness.
Constitution - All classes can benefit from a high physical power score, as it affects maximum HP, HP regeneration speed, knockdown resistance and spiritual resistance.
Dexterity - Affects attack power and accuracy of firearms, blocking rate, critical rate , attack speed of light weapons. This is the most important stat for musketeers.
Intelligence - This determines magical attack power and elemental resistances. Elementalists and Wizards need a high Intelligence score.
Charm - Affects the overall power of summoned monsters. The higher the charm number, the stronger the summoned monster.